Potatoes offer more than just carbs

Q: I recently saw a list of foods with high vitamin C content, and potatoes were on the list! Is that really true? I thought they were just carbs.

Answer: It is true: Potatoes are a decent source of vitamin C. A medium raw potato, peel and all, has 40 to 45 milligrams of vitamin C. That’s about 40 percent of a daily requirement. Some of the C is in the peel but most is in the flesh.

Microwaving the potato with or without the skin will preserve most of the vitamin C. Baking it will destroy a little vitamin C, but more is lost if you boil it. Probably a lot of it leaches out into the water. Frying them will destroy even more in the higher heat.

Potatoes also have a lot of potassium, almost double what a banana has. And they’re decent sources of fiber as well. The fiber is in both the skin and the flesh, so you don’t have to force yourself to eat the skin if you don’t want to.

The biggest problem with potatoes is how we cook them and what we put on them. Fried in grease, or baked and slathered with sour cream and butter — more grease — really adds the calories, and piles on the pounds. Sprinkling with salt doesn’t help our blood pressure, and dipped in ketchup (tomato jam, really) adds more sugars and salt. But potatoes, without all the additives, are good nutrition.

Q: I’ve noticed that there are a couple of brands of margarine that say on the container that they will help lower cholesterol. But when I look at the nutrition box they don’t seem to be much different at all from the regular brands. What gives some of them the right to say they’ll lower cholesterol and others not? Or will all margarine do that?

Answer: A few brands have passed the FDA’s approval process and are allowed to make that claim on their labels. No margarine contains cholesterol unless it contains dairy products, because cholesterol is only an animal product. However, most of the cholesterol in our blood is made by our livers from the saturated fat that we eat, and most margarine does have saturated fat. So we could use only margarine and still end up having more cholesterol in our blood. But some do have an additional ingredient that helps lower it.

What you want to look for on the label is a statement that the product contains “plant sterols” or “plant sterol esters” or “plant stanol esters.” These things, made naturally in all plants but especially in some (such as soybeans, nuts and whole grains), are very similar to cholesterol. But they’re just slightly different. And the difference is enough that when our guts try to absorb them like cholesterol, they “get stuck in the doorway.” They are not absorbed, and they block up the doorway so that we can’t absorb any cholesterol in the meal.

If you eat enough of them over a period of time, your blood cholesterol will probably start going down. How much margarine you need is stated on the label for each brand. They won’t help if you’re a vegetarian, because there won’t be cholesterol in vegetarian meals. And they won’t help as much if you already eat a diet that is low in cholesterol. But if you’re eating a regular American diet, and exchange your regular butter or margarine for one of these brands, they probably will help bring your numbers down.

Mary A. Keith, a licensed dietitian and health agent at Hills borough County Extension, can be reached at mkeith@ufl.edu.